Expose `move` & add `claimDataLen`

packages/contracts-bedrock/.gas-snapshot

@@ -32,30 +32,30 @@ DisputeGameFactory_SetImplementation_Test:test_setImplementation_notOwner_revert
 DisputeGameFactory_SetImplementation_Test:test_setImplementation_succeeds() (gas: 44243)
 DisputeGameFactory_TransferOwnership_Test:test_transferOwnership_notOwner_reverts() (gas: 15950)
 DisputeGameFactory_TransferOwnership_Test:test_transferOwnership_succeeds() (gas: 18642)
-FaultDisputeGame_ResolvesCorrectly_CorrectRoot2:test_resolvesCorrectly_succeeds() (gas: 502842)
-FaultDisputeGame_ResolvesCorrectly_CorrectRoot3:test_resolvesCorrectly_succeeds() (gas: 504699)
-FaultDisputeGame_ResolvesCorrectly_CorrectRoot:test_resolvesCorrectly_succeeds() (gas: 492706)
-FaultDisputeGame_ResolvesCorrectly_IncorrectRoot2:test_resolvesCorrectly_succeeds() (gas: 501717)
-FaultDisputeGame_ResolvesCorrectly_IncorrectRoot3:test_resolvesCorrectly_succeeds() (gas: 503574)
-FaultDisputeGame_ResolvesCorrectly_IncorrectRoot:test_resolvesCorrectly_succeeds() (gas: 491581)
-FaultDisputeGame_Test:test_defendRoot_invalidMove_reverts() (gas: 13250)
-FaultDisputeGame_Test:test_extraData_succeeds() (gas: 17448)
+FaultDisputeGame_ResolvesCorrectly_CorrectRoot2:test_resolvesCorrectly_succeeds() (gas: 498826)
+FaultDisputeGame_ResolvesCorrectly_CorrectRoot3:test_resolvesCorrectly_succeeds() (gas: 500705)
+FaultDisputeGame_ResolvesCorrectly_CorrectRoot:test_resolvesCorrectly_succeeds() (gas: 488169)
+FaultDisputeGame_ResolvesCorrectly_IncorrectRoot2:test_resolvesCorrectly_succeeds() (gas: 497701)
+FaultDisputeGame_ResolvesCorrectly_IncorrectRoot3:test_resolvesCorrectly_succeeds() (gas: 499580)
+FaultDisputeGame_ResolvesCorrectly_IncorrectRoot:test_resolvesCorrectly_succeeds() (gas: 487044)
+FaultDisputeGame_Test:test_defendRoot_invalidMove_reverts() (gas: 13294)
+FaultDisputeGame_Test:test_extraData_succeeds() (gas: 17426)
 FaultDisputeGame_Test:test_gameData_succeeds() (gas: 17873)
-FaultDisputeGame_Test:test_gameStart_succeeds() (gas: 10337)
-FaultDisputeGame_Test:test_gameType_succeeds() (gas: 8216)
-FaultDisputeGame_Test:test_initialRootClaimData_succeeds() (gas: 17691)
-FaultDisputeGame_Test:test_move_clockTimeExceeded_reverts() (gas: 26410)
-FaultDisputeGame_Test:test_move_duplicateClaim_reverts() (gas: 103231)
-FaultDisputeGame_Test:test_move_gameDepthExceeded_reverts() (gas: 407967)
-FaultDisputeGame_Test:test_move_gameNotInProgress_reverts() (gas: 10923)
-FaultDisputeGame_Test:test_move_nonExistentParent_reverts() (gas: 24632)
-FaultDisputeGame_Test:test_resolve_challengeContested() (gas: 221068)
-FaultDisputeGame_Test:test_resolve_notInProgress_reverts() (gas: 9657)
-FaultDisputeGame_Test:test_resolve_rootContested() (gas: 106120)
-FaultDisputeGame_Test:test_resolve_rootUncontested() (gas: 23624)
-FaultDisputeGame_Test:test_resolve_teamDeathmatch() (gas: 391731)
-FaultDisputeGame_Test:test_rootClaim_succeeds() (gas: 8203)
-FaultDisputeGame_Test:test_simpleAttack_succeeds() (gas: 107322)
+FaultDisputeGame_Test:test_gameStart_succeeds() (gas: 10315)
+FaultDisputeGame_Test:test_gameType_succeeds() (gas: 8238)
+FaultDisputeGame_Test:test_initialRootClaimData_succeeds() (gas: 17713)
+FaultDisputeGame_Test:test_move_clockTimeExceeded_reverts() (gas: 26432)
+FaultDisputeGame_Test:test_move_duplicateClaim_reverts() (gas: 103275)
+FaultDisputeGame_Test:test_move_gameDepthExceeded_reverts() (gas: 408100)
+FaultDisputeGame_Test:test_move_gameNotInProgress_reverts() (gas: 10968)
+FaultDisputeGame_Test:test_move_nonExistentParent_reverts() (gas: 24698)
+FaultDisputeGame_Test:test_resolve_challengeContested() (gas: 221135)
+FaultDisputeGame_Test:test_resolve_notInProgress_reverts() (gas: 9635)
+FaultDisputeGame_Test:test_resolve_rootContested() (gas: 106143)
+FaultDisputeGame_Test:test_resolve_rootUncontested() (gas: 23625)
+FaultDisputeGame_Test:test_resolve_teamDeathmatch() (gas: 391864)
+FaultDisputeGame_Test:test_rootClaim_succeeds() (gas: 8159)
+FaultDisputeGame_Test:test_simpleAttack_succeeds() (gas: 107388)
 FeeVault_Test:test_constructor_succeeds() (gas: 18185)
 GasBenchMark_L1CrossDomainMessenger:test_sendMessage_benchmark_0() (gas: 352135)
 GasBenchMark_L1CrossDomainMessenger:test_sendMessage_benchmark_1() (gas: 2950342)

packages/contracts-bedrock/contracts/dispute/FaultDisputeGame.sol

@@ -72,12 +72,12 @@ contract FaultDisputeGame is IFaultDisputeGame, Clone, Semver {
 
     /// @inheritdoc IFaultDisputeGame
     function attack(uint256 _parentIndex, Claim _pivot) external payable {
-        _move(_parentIndex, _pivot, true);
+        move(_parentIndex, _pivot, true);
     }
 
     /// @inheritdoc IFaultDisputeGame
     function defend(uint256 _parentIndex, Claim _pivot) external payable {
-        _move(_parentIndex, _pivot, false);
+        move(_parentIndex, _pivot, false);
     }
 
     /// @inheritdoc IFaultDisputeGame
@@ -162,11 +162,11 @@ contract FaultDisputeGame is IFaultDisputeGame, Clone, Semver {
     /// @param _challengeIndex The index of the claim being moved against.
     /// @param _pivot The claim at the next logical position in the game.
     /// @param _isAttack Whether or not the move is an attack or defense.
-    function _move(
+    function move(
         uint256 _challengeIndex,
         Claim _pivot,
         bool _isAttack
-    ) internal {
+    ) public {
         // Moves cannot be made unless the game is currently in progress.
         if (status != GameStatus.IN_PROGRESS) {
             revert GameNotInProgress();
@@ -254,6 +254,11 @@ contract FaultDisputeGame is IFaultDisputeGame, Clone, Semver {
         l2BlockNumber_ = _getArgUint256(0x20);
     }
 
+    /// @notice Returns the length of the `claimData` array.
+    function claimDataLen() external view returns (uint256 len_) {
+        len_ = claimData.length;
+    }
+
     ////////////////////////////////////////////////////////////////
     //                    `IDisputeGame` impl                     //
     ////////////////////////////////////////////////////////////////

packages/contracts-bedrock/contracts/test/FaultDisputeGame.t.sol

@@ -391,7 +391,7 @@ contract GamePlayer {
 
                 // Now, search for the index of the claim that commits to the prestate's trace
                 // index.
-                uint256 len = claimDataLen();
+                uint256 len = gameProxy.claimDataLen();
                 for (uint256 i = 0; i < len; i++) {
                     (, , , Position pos, ) = gameProxy.claimData(i);
                     if (Position.unwrap(pos) == Position.unwrap(statePos)) {
@@ -424,7 +424,7 @@ contract GamePlayer {
                 // Attack the parent claim.
                 gameProxy.attack(_parentIndex, ourClaim);
                 // Call out to our counter party to respond.
-                counterParty.play(claimDataLen() - 1);
+                counterParty.play(gameProxy.claimDataLen() - 1);
 
                 // If we have a second move position, attack the grandparent.
                 if (Position.unwrap(movePos2) != 0) {
@@ -432,22 +432,17 @@ contract GamePlayer {
                     Claim ourGrandparentClaim = claimAt(grandparentPos.move(true));
 
                     gameProxy.attack(grandparentIndex, ourGrandparentClaim);
-                    counterParty.play(claimDataLen() - 1);
+                    counterParty.play(gameProxy.claimDataLen() - 1);
                 }
             } else {
                 // Defend the parent claim.
                 gameProxy.defend(_parentIndex, ourClaim);
                 // Call out to our counter party to respond.
-                counterParty.play(claimDataLen() - 1);
+                counterParty.play(gameProxy.claimDataLen() - 1);
             }
         }
     }
 
-    /// @notice Returns the length of the claim data array.
-    function claimDataLen() internal view returns (uint256 len_) {
-        return uint256(vm.load(address(gameProxy), bytes32(uint256(1))));
-    }
-
     /// @notice Returns the state at the trace index within the player's trace.
     function traceAt(Position _position) public view returns (uint256 state_) {
         return traceAt(_position.traceIndex(maxDepth));